Anti-GM1 ganglioside antibodies with differing fine specificities in patients with multifocal motor neuropathy

Antibodies to gangliosides were detected in sera from three of 19 patients with chronic inflammatory polyneuropathy (CIP) by a thin-layer chromatogram overlay technique. All three of the patients fell into a clinical subset of the group that had multifocal motor neuropathy, and in all three patients the antibodies reacted with GM1 ganglioside. However, the fine specificities of the antibodies differed as demonstrated by cross-reactivity with different gangliosides in each of the three patients. The antibodies in patient 1 reacted with GM1, GD1b, and asialo-GM1 suggesting that the terminal Gal(beta 1-3)GalNAc moiety that is common to these three glycolipids is an important part of the epitope(s). This was confirmed by showing reactivity of the antibodies with Gal(beta 1-3)GalNAc conjugated to bovine serum albumin. Patient 2 had antibodies that did not react with GD1b, but cross-reacted with GM2 ganglioside suggesting that the epitope(s) involved the inner portion of the oligosaccharide moiety that is shared between GM1 and GM2. Patient 3 had antibodies that reacted with GM1 and asialo-GM1, but they did not cross-react with either GD1b or GM2. These results provide further evidence for a relationship between motor nerve syndromes and anti-GM1 antibodies and also suggest that GM1 could be a principal target antigen since other reactive gangliosides differed among the patients. However, the possible pathogenic effects of anti-GM1 antibodies on motor nerves remain to be established.